Quantitative population dynamics of microbial communities in plankton-fed microbial fuel cells

Abstract

This study examines changes in diversity and abundance of bacteria recovered from the anodes of microbial fuel cells (MFCs) in relation to anode potential, power production and geochemistry. MFCs were batch-fed with plankton, and two systems were maintained at different potentials whereas one was at open circuit for 56.8 days. Bacterial phylogenetic diversity during peak power was assessed from 16S rDNA clone libraries. Throughout the experiment, microbial community structure was examined using terminal restriction fragment length polymorphism. Changes in cell density of key phylotypes, including representatives of d-, e-, c-proteobacteria and Flavobacterium-CytophagaBacteroides, were enumerated by quantitative PCR. Marked differences in phylogenetic diversity were observed during peak power versus the final time point, and changes in microbial community structure were strongly correlated to dissolved organic carbon and ammonium concentrations within the anode chambers. Community structure was notably different between the MFCs at different anode potentials during the onset of peak power. At the final time point, however, the anode-hosted communities in all MFCs were similar. These data demonstrate that differences in growth, succession and population dynamics of key phylotypes were due to anode potential, which may relate to their ability to exploit the anode as an electron acceptor. The geochemical milieu, however, governs overall community diversity and structure. These differences reflect the physiological capacity of specific phylotypes to catabolize plankton-derived organic matter and exploit the anode of an MFC for their metabolism directly or indirectly through syntrophy.

Microbial population and functional dynamics associated with surface potential and carbon metabolism

“…These studies revealed that different EETactive communities were established with various carbon substrates and different electrode potentials, and both parameters clearly affected the final community composition (Torres et al, 2009;White et al, 2009;Freguia et al, 2010;Kiely et al, 2011). However, it is poorly understood how the substrates and electrode potentials affect the developmental processes of EET-active microbial communities, and how metabolic networks are established and maintained within the community.…”

Live wires: direct extracellular electron exchange for bioenergy and the bioremediation of energy-related contamination

“…In organic-rich sediments this may be members of the Geobacteraceae family 38,137 or other organisms. 138 Sulfide can be an important electron donor in sulfide-rich sediments. The abiotic oxidation of sulfide to elemental sulfur can provide some electrons, and then microorganisms such as Desulfobulbus, 139 can oxidize the elemental sulfur to sulfate, increasing the current contribution from sulfide.…”

The Influence of Energy Harvesting Strategies on Performance and Microbial Community for Sediment Microbial Fuel Cells

“…This outcome is similar the study by White et al who reported that communities were most different during startup and the similar community structures were observed once steadystate power had been achieved. 41 That study indicated that a diverse community structure had populated the anodes by peak power. This diversity was reduced under steady-state power production, indicating that the entire community observed in during SMFC startup does not contribute to electricity production.…”